This project is a study of the feasibility of a larger project that will seek to interpret the most consistent and general result in the field of psychiatric epidemiology: that lower class individuals are more likely to be mentally disordered than those from the upper class. Two interpretations are possible: that stresses associated with lower class life produce more disorder (stress); or that the mental disorder hinders the attainment of appropriate social class status (selection). This stress-selection tissue ties into the more general debate on the relative weight of heredity and environment in the causation of mental disorder. A quasi-experiment to resolve this issue has been designed by Bruce and Barbara Dohrenwend of Columbia University. It takes advantage of discriminatory pressures of varying force against ethnic groups in large cities. The Dohrenwend quasi-experiment necessitates three assumptions concerning cross cultural differences: that different ethnic groups have identical levels of occupational aspiration; that different ethnic groups have similar genetically-determined predispositions to mental disorder; and that it is possible to measure levels of mental disorder equivalently across cultures. This research, a revision of the Dohrenwend quasi-experiment, eliminates the necessity for all three assumptions by studying the same ethnic group (North African Jews) in contexts with diverse environments of discrimination (Quebec and Israel). Anglophone Jews and majority groups (French Canadians and Sabras) serve as controls, as well as independent replications of the quasi-experiment. Samples of the general population of French Canadians, Anglophone Jews, and North Africans in Quebec (and Sabras, Anglophone Jews, and North Africans in Israel) will be surveyed with instruments designed to yield diagnoses of neurosis and personality disorder. A facility search for schizophrenics and affective psychoses will be carried out for four group@ (Anglophone Jews and North Africans in Quebec and Israel). The research will integrate past findings concerning class and mental disorder, and provide indirect but vital evidence on the stress-selection issue. It will specify more precisely the effects of the system of socioeconomic stratification on the mental life of individuals in our society.